1. Field of the Invention
The present disclosure generally relates to systems for and methods of producing surface wrinkles. More particularly, the invention pertains to a system for and method of actively producing surface wrinkles using active material actuation, and more applicably, shape memory alloy and shape memory polymer activation.
2. Discussion of Prior Art
Surface wrinkles have been used to effect, modify, or control various benefits/conditions, including surface adhesion, reflection, texturing, coefficients of friction, structural colors, metrology, and haptic alerts. Methods of producing surface wrinkles preexisting in the art include using a stretched substrate overlaid by a rigid (e.g., metal) overlay. Wrinkles are instantaneously or selectively produced in the overlay, upon the release of energy by the substrate, if the compressive strain in the overlay exceeds the critical bucking strain. As a result, these conventional methods produce generalized wrinkles that co-extend with the entire surface defined by the overlay. This method is in fact behind wrinkles commonly encountered, for example, on human skin and dehydrated apples. Of particular interest is that the wrinkle geometry is closely related to the material properties. Precisely controlled wrinkle structures have found many interesting applications including nano-metrology, stretchable electronics, biosensors, and manipulation of material topographic properties.